Acoustic hobn



April 19,1927. 1,625,325

J. MACARTNEY ET AL ACOUSTIC HORN Filed Dec. 26, 1924 n Ira/Gator; -6U,(li1ws. s' I Jaclamcarinejy 16 h Patented Apr. 19, 1927.

UNITED STATES I 1,625,325 PATENT OFFICE.

JACK MACARTNEY AND ARCHIE V. HAHN, OF LOS ANGELES, CALIFORNIA.

ACOUSTIC HORN.

Application filed December 26, 1924. Serial No. 758,086.

Our invention relates particularly to means for increasing the volume of sound waves reproduced by a radio or phonograph loud speaking unit, and an object of this invention is the provision of novel means for the reproduction of-music and the human voice and other sounds received by radio, phonograph records, etc.

Another object is to provide a novel acoustic horn .which forms in itself a neat appearing cabinet.

Another object is to provide a horn of e character set forth which is very compact without destroying or impairing the efliciency thereof. In other words, by. our invention a small compact horn havinga length of about eight inches is capable of producing as good results as a horn of the old style having a length of approximately twenty-four inches.

A further object of this'in'vention is to provide a novel tone path in which the tone waves or sound vibrations are enabled to expand in a uniform progressively increasing path, thus giving ample volume without distortion of the sound.

I A still further object is to provide a novel horn-which is square in cross section, thus producing slight.- differences in the and modulate the tone.

Other objects are cheapness of construction andeaseof assembl Another. object is -to provide a noval conwave pathswhich produce sliglit' harmonics struction wherebya horn of this character may be made frompanels having contours formed by a moulding machine.

Other objects,-advantages, and features of invention mayappear from the accompanying drawing, the ineddetailed'descrip tion and .theappended' claims.

The accompanying. drawingillustrates the invention in one of the forms .we at present deem preferable.

Figure 1 is aside elevation of our horn.

Fig. 2 is a froiitview fithe sam'e. f Fig. 3 is a longitudinal.sectional view'of the same, indicated bylinerv, Fig. 2.

Fig. 4 is a erspective view of one of the panels us to form the outer horn. Fig. 5 isa section .on line 91 Fi 3; Referring more particularlyto t e draw ing our horn consists of a pro ressively increasing tone path which itself and comprises three sound conduits, an inner horn 1', a secondary horn 2 surroundthe panels 4 dou les back on ing the inner horn and in spaced relation thereto, and an outer horn3 which forms the bell of the horn and in which both the inner and secondary horns are mounted, and said outer horn is in spaced relation to the secondary horn. The horns 2 and 3 are shown as rectangular in length and square in cross section and are described as such for the sake of brevity, but it is understood that the cross section of the horns may be a polygon having any number of sides. The secondary horn 2 has a pointed outer end which with the outwardly extending curve 5 of the outer horn 3 formsa bell for the horn which flares outwardlyin an approved manner and prevents undue interference of the sound Waves as they are emitted from the horn.

The horn 3, is formed of four rectangular panels 4, the inner surfaces of which taper towards the front, which in F ig. 3 is shown at the top, and are forni'edwith anout- 'wardly extending curve 5 at the front which forms the'bell of the horn. The outer surfaces of the panels l'a're suitably decoratively cut so that when the plurality of panels forming the outer horn are assemibled they form apleasing cabinet 'appearance for the entire horn. It will be noted, and one of the advantages of myi invention is, that through an" ordinary mou ldingp machine. The"panelsf are then cut'tojwidth and the longitudinal edges :mite'red' as v at. 6' and fit together to form the completed horn. Although the horn 1 and block 15 are "shown as separate pieces" itf'is app arent that the same may be made 'in'a single piece;'and it may be said that'the inner horn is mounted in the'outer horn or in the rabbet 16 formed in the outer horn. Th'e panels may be joined together by anysuitable means, preferably by gluing. Agrill? is mounted in a rabbet'8 formed at the front end of the horn 3.

The-secondary horn is supported by the grill and isj suspended within and in spaced relation to,'the outer horn 3. Ascrew 9 extending through the grill 7 and 1nto the top of the horn 2 secures the horn '2 in fixed relation to the horns 1 and 3. The rearor inner end of the horn 2 flares rearwardly and outwardly fromthe front of the horn and approaches the inner surface of the horn 3, thus constricting the passage at the lower end thereof.

are formed by moving them their lower ends as previously The horn 2 is also square in cross section and is formed of substantially triangular panels 10. These panels are formed with their outer surfaces curving from the rear of the horn, outwardly and inwardly as at- 11 to form a blunt point, and diverge at described.

A deflecting point 12 is mounted centrally within the horn 2 at the front thereof, and extends a slight distance into the horn 1. The point 12 is fitted into rabbets 12' formed in the panels and is provided with curved surfaces which tend to curve over the front edge of the horn 1. The inner 'surfaces of the panels 10 are curved rearwardly and o he ha to fo m a ing tone path. The

end 19 which is received in a bore centrally outwardly from the point 12 as at 13 to provide a smooth deflecting surface which will not distort or reflect the sound.

The horn 1 is not shown as forincd of panels, but is referably made of a single block of wood or other fibrous material throughwhich a tapered round bore let-extends. This bore diverges towards the front progressively increashorn 1 has a reduced formed in a blo k 15 which rests in ajrabbet thepa-nels 4 at the rear end of .1 f rmed in the. horn 3, The block 15 has its inner surfacecurved as at 17. The inner surface of" the h rn 3 1S curv d inwa y as at 1 to meet the curved surface 17 of block 15, to forn a deflecting surface as will be further described.

A phone or speaker unit 20 of any well knowneonstruct'ion is mounted at one end of the hore 14, and' the leads 21 thereof 22 in the lower extend through an opening. nd (I n f he P n as-1M adj st ng screw 22 extends through the rear closure. 23 which is mounted in rahbets formed .in the panels 4: at the rear outside end thereof. u i 2 Pref a y has a n ppl 20 which fits into. th bore 1 k and retains the unit in assembled positiom The .tone or sound waves emitted'by the speaker unit 20 travel forwardly in the bore 14, and at the front thereof the tone waves -ar.e. deflected and split by the tip 12 and surfaces 13, in four or more directions, depending on the number 2. The sound then travels rearwardly along the diverging path 25 formed between the horns 1 and2 is again V in four or more reverse directions by the surfaces 17 and 18 and the sound then travels frontwardly in the diver-gin passage 26 formed betweenthe horns 2 an 3.

The sound in passing from the bore 14 into, passage 25 passes through the curved entrance 27, which is formed by the front edge of the horn 1 and the diverging walls 2, and again in passing from of the horn the passage 25 to the'pa-ssage 26 it passes through of sidesin the horn deflected and split horn extends,

the curved entrance 28, which is' formed by the rear-endof the horn 2 and the curved walls'of the horns 1 and 3. This prevents a loud blast, and a consequent distortion of sound in 'the horn because the walls of the horn are so curved and spaced from'each other that the area of the tone. path constantly progressively increases.

The curvature o'f 'the walls along which the sound waves travel are such that there is a minimum amount of resistance and rcfiection. The inward curvature of the outer and front end of the horn 2, .i. e., at the curves 11, leaves the bell of the horn or in other words the. front or outer end 'of the horn 3 practically free of any obstructions and the sound waves pass outwardly from the horns. without interference or damping. Referring to Fig. 3 it will be noted that the outer free edge 'of horn 1 .is'cl'oser to the inner surface of horn 2 thanthe inner free edge of horn 1 is tothe point 12; and the inner rear surface of horn is spaced at greater d stance from born 1 than the cross sectional thickness to providean" in ereasedarea oftor' e path. The"sarne is true at' 't lic"in'nr' eud' 'of'horns' 2 and 3. The tone path'in each of the horns is so constructed, and-5 especially at the deflecting 'or junction points of th'e horns, that it' suc-' cessively progressively "increases 1n area from one end of the horn to the other. This construction reduces to a minimum distortion j of .the' 'soundfwav'es which distortion hasbeeh ver noticeable heretofore inhorns in which the tone path doubles"ba'cl r upou itself Qur produotidn is "entirel fibrous material such as" wood 2 is suspended from the wooden grill 7,

thus eliminating all Qliarsh metallic sounds and vibrations." i I By the foregoing construction it will be seen that. .the tone pathdqubles backu-pon itself an'd'the sound waves are splitin eight .or inoredirecti'ons; and that the curves'at the mint of'the'liorns 1; 2 and attlt rear of'the horns 2, 3 are such that the sound waves are not reflected back into the-same passage but instead deflect the waves from horn 1 into horn 2 and from horn 2 into horn 3. B deflecting the waves without reflecting t ern 'we provide a horn which will'not distort the sound.

1. An acoustic'horn' comprising an inner horn,"a second horn into whichfsaid inner said second h'orn'bein-g formed of a plurality of panels,- vand-an enter horn in spaced relation to outer liorn'being formed ofa plurality of said second horn, said panels, which when assembled form a cabinet inclosing the inner and second horn and forming therewith the entire horn,

2. An acoustic horn comprising an inner horn, a second horn into which said inner horn extends, said second horn being formed of a plurality of panels, and an outer horn in spaced relation to said second horn, said outer horn being formed of a plurality of panels which entirely inclose the inner and second horns and the panels of which said second and outer horns are formed being sections of molding.

3. In a device of the character set forth an inner horn, a second horn in spaced relation to said inner horn, an outer horn in spaced relation to said second born a grill over the end of said outer horn, an means to secure said second horn to said grill.

4. An acoustic horn comprising in combination an inner horn, a second horn in spaced relation to said inner ho'rn, an outer horn in spaced relation to said second horn, a grill over the end of said outer horn, means to secure said second horn to said grill, said inner horn being secured to said outer horn and adapted to be provided with a phone unit mounted to extend into said inner horn.

5. An acoustic horn comprising an inner horn, a second horn in spaced relation to said inner horn; said second horn being square in cross section and formed of a plurality of sections of molding, an outer horn in spaced relation to said second horn said outer horn being square in cross section and formed of a plurality of sections of molding, means to support said inner horn and said second horn from said outer horn, and

adapted to be provided with a phone unit extending into said inner horn.

6. An acoustic horn comprising an outer horn provided at one end with a block; an inner horn mounted in said block; a grill secured to the other end of said outer horn; a second horn encircling said inner horn and supported bv said outer horn in spaced relation to said outer horn and to said inner horn; and a deflecting point in said second horn extending a slight distance into the inner horn.

7. As an article of manufacture, rectangular panels having outwardly curved surfaces to form the bell of a horn and provided with rabbets; a. block mounted in said rabbet; another block provided with a tapered bore and having a reduced end mounted in said first mentioned block; panels having curved surfaces to form with said rectangular panels and with said other block a tone path; and a deflecting point mounted in the meeting point of said triangular shaped panels.

8. In a device of the character set forth, an inner horn, a second horn in spaced relation to said inner horn, an outer horn in spaced relation to said second horn, a grill inclosing the end of said outer horn, a screw element for securing said grill to said second horn, and a block secured to said outer horn for supporting said inner horn. in position centrally of said outer horn,

In testimony whereof, we have hereunto set our hands at Los Angeles, California, this 18th day of December, 1924.

JACK MACARTNEY. ARCHIE V. HAHN. 

